Simple assert, move code around, note a bug.
rewire() to rewire end streams, too.
Pretend that README is .md, too.
Add TODOs.
Rename it to 'xstream'.
Rename to xstream.js.
Fix require test.
Fix 'mk'.
Browser usage.
Fix cells.html.
take().
Fix explore.
.withState(), use it.
Add TODO stuff.
What was that doing there.
Fix embarrassing bug in .commit().

Children were updated even if none of their parents were -- which broke
slice() totally.
Add 'spec' directory for more detailed tests.
skip, slice, slidingWindow.
leave(n), combineWhenAll() (just for testing for now).
Update TODO.